<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Cover for Steven</title>
  <style>
    body {
      background: #ececec;
    }

    .box {
      position: absolute;
      left: 50%;
      top: 50%;
      transform: translate(-50%, -50%);

      background: #fff;
      width: 600px;
      height: 400px;
      box-shadow: -10px 10px 10px rgba(0, 0, 0, .1);
    }

    .cover-text {
      margin: 20px;
      margin-top: 100px;
      text-align: center;
      font-size: 80px;
      font-weight: bold;
      color: #939393;
    }

    .band span {
      background: #3699d5;
      /* 视频中的CSS */
      /* background: #4E5C93; */
      /* 视频中的PHP */
      /* background: #FA8A2A; */
      /* 视频中的SVG */
      /* background: linear-gradient(to right, #355BC9, #6D38D7); */
      /* 视频中的Unboxing */

      color: #fff;

      width: 225px;
      font-size: 24px;
      font-weight: bold;
      padding: 8px 0;

      position: absolute;
      transform: rotate(45deg);
      left: -25px;
      top: 30px;
      /*   text-shadow:0 1px 1px rgba(0,0,0,.2); */
      text-align: center;
      /*   box-shadow:0 10px 10px rgba(0,0,0,.1); */
      /*   这里其实是有所瑕疵的 */
      /*   box-shadow:0 10px 10px black;作为阴影 形状是不对的 */
    }

    .band {
      position: absolute;
      width: 150px;
      height: 150px;
      overflow: hidden;
      top: -10px;
      right: -10px;
    }

    .band::before,
    .band::after {
      border: 5px solid #2880b8;
      /* 视频中的CSS */
      /* border: 5px solid #434B77; */
      /* 视频中的PHP，Unboxing同 */
      /* border: 5px solid #E35B1B; */
      /* 视频中的SVG */

      content: '';
      /*   要加content伪元素才能显示 */
      position: absolute;
      border-top-color: transparent;
      border-right-color: transparent;
      /*   来形成三角形 */
    }

    .band::after {
      bottom: 0;
      right: 0;
    }
  </style>
</head>

<body>
  <div class="box">
    <p class="cover-text">蹭Steven热度专用封面</p>
    <div class="band wband">
      <span>CSS</span>
    </div>
  </div>
</body>

</html>